KR0120450Y1 - Apparatus for delivering a silica film forming solution - Google Patents

Abstract

There is a discharge device for delivering a fixed amount of silica coating liquid from the liquid reservoir to the substrate surface in order to form a silica film on the substrate surface. The liquid storage tank that stores the silica coating liquid is connected to the diaphragm pump through the suction pipe. The diaphragm pump is bound to the nozzle through the delivery pipe. In the liquid reservoir, the coating liquid is supplied to the nozzle by suction and discharge of the diaphragm pump. The coating liquid is discharged from the nozzle to the substrate surface supported by the rotary chuck of the rotary coating device.

Description

Apparatus for discharging coating liquid for forming silica film

1 is a view showing the main part of a rotary coating device having a device for discharging a coating liquid for forming a silica film according to the present invention,

2 is a perspective view of a diaphragm pump used in the apparatus according to the present invention,

3 is a longitudinal sectional view of the diaphragm pump,

4a and 4b are views showing the valve configuration in the diaphragm pump,

5a and 5b illustrate an improved diaphragm pump,

6 is a time chart for explaining the suck back operation of the diaphragm pump,

7A, 7B, and 7C are schematic diagrams showing modifications of the apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Liquid reservoir 2: Liquid suction pipe

3: diaphragm pump 3a: liquid suction port of diaphragm pump

3b: liquid delivery port of the diaphragm pump 4: liquid delivery pipe

5: nozzle 6: rotating chuck

W: Wafer S: Silica Film-forming Coating Liquid

The present invention relates to a device used in a rotary coating device for discharging a coating liquid for forming a silica film on the surface of a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal display device.

A conventional apparatus for discharging a coating liquid is disclosed in, for example, Japanese Patent Laid-Open No. 1989-52065 (Japanese Patent Laid-Open No. 1985-12175).

This type of liquid dispensing apparatus has a closed container for storing the coating liquid and is compressed by introducing nitrogen gas or helium gas into it. The coating liquid is configured to drop from the vessel to the substrate surface through the supply pipe under pressure.

Another type of apparatus employs a bellows pump for delivering the photoresist as a coating liquid dripping onto the substrate surface. That is, the bellows pump draws out a coating liquid such as a photoresist and sends out a coating liquid for application to the surface of the substrate.

The known device suffers from various obstacles as described later.

The apparatus using gas pressure when nitrogen gas is used to be introduced into an airtight container has the following inconveniences.

Nitrogen gas is easily dissolved in the coating liquid. Nitrogen gas dissolved in the coating liquid may appear as bubbles during delivery of the coating liquid, or degassing may occur after application to the substrate. As a result, pinholes appearing in the film formed on the substrate or the coating liquid is not applied uniformly, resulting in low productivity.

Where helium gas is used instead of nitrogen gas, the gas is less soluble in the coating liquid. However, helium gas is expensive, so high operating costs create another problem.

The apparatus using the bellows pump is free from gas dissolution and high operating cost problems in the coating liquid because no gas is used, but since the coating liquid forms a silica film, there are the following obstacles.

That is, in the bellows pump, the coating liquid is sucked and sent out by the expansion and contraction of the bellows, but due to its structure, all of the sucked coating liquid is not sent out at the time of sending, and a part of the applied coating liquid can remain in the bellows pump for a long time. Will be. Moreover, since a silica film formation coating liquid generally has the property of being easy to crystallize, when a silica film formation coating liquid remains in a bellows pump, the crystal | crystallization of a silica film formation coating liquid produces | generates in a bellows pump. As a result, in the bellows pump, the coating liquid in which the crystals are mixed is sent out and discharged to the substrate surface. When the substrate is rotated to form a film of the coating liquid, crystals adhere to the substrate surface and are not evenly distributed in the vicinity of the crystals, so that a uniform film is not obtained.

The present invention has been made in view of the above circumstances, and it is a device which prevents the dissolution of gas into the coating liquid, prevents the operating cost from becoming high, and supplies the coating liquid to the substrate surface for the formation of a silica film which is easy to crystallize. It is an object to provide an apparatus for discharging a coating liquid for forming a silica film from which a good film is obtained.

In order to achieve this object, the present invention adopts the following configuration. That is, the apparatus according to the present invention comprises a rotary coating device for rotating the substrate horizontally to form a film of the coating liquid dropped on the surface of the substrate, wherein the silica film for discharging the coating liquid for forming a silica film on the surface of the substrate. In the apparatus for discharging a coating liquid for formation,

The device is:

A liquid storage tank in which a coating liquid for forming a silica film is stored;

A nozzle facing the substrate surface for spraying the coating liquid;

A diaphragm pump for sucking the coating liquid from the liquid reservoir and sending it to the nozzle;

A suction pipe having one end connected to the coating liquid stored in the liquid storage tank and the other end connected to the suction port of the diaphragm pump;

One end is composed of a liquid discharge pipe connected to the outlet of the diaphragm pump and the other end is connected to the nozzle.

Diaphragm Pump:

A pump chamber in which the diaphragm is extended;

A suction valve for opening and closing a liquid suction flow passage communicating the liquid suction pipe and the pump chamber with each other;

It is composed of a delivery valve for opening and closing the liquid delivery flow passage for communicating the delivery pipe and the pump chamber with each other.

Again, the device is:

A pump driving device for reciprocating the diaphragm in the pump chamber;

A suction valve driving device for operating the suction valve;

Consists of a delivery valve drive device for operating the delivery valve, a pump drive device, a suction valve drive device and control devices for controlling the delivery valve drive device, the diaphragm pump drives the suction and delivery of the coating liquid.

According to this apparatus, in the suction operation of the diaphragm pump, the silica coating liquid is sucked into the diaphragm pump through the suction pipe in the storage tank. Next, in the discharging operation of the diaphragm pump, the silica coating liquid sucked from the storage tank is discharged to the liquid discharging pipe through the nozzle and discharged onto the substrate surface.

Since gas is not used for discharging the coating liquid onto the substrate surface, there is no dissolution of the gas in the coating liquid which causes trouble as degassing after application to the substrate surface or gas bubbles during transfer. In addition, the present invention does not calculate a high operating cost by using expensive gas. In addition, the amount of the silica coating liquid applied to the substrate surface can be controlled with high accuracy as compared with the case of using gas input.

In the suction / discharge operation (single stroke) of the diaphragm pump, almost all of the suction coating liquid is consumed. The coating liquid has less crystallization and residual opportunities in the diaphragm pump than the bellows pump. The silica coating liquid supplied to the substrate surface does not contain crystals that degrade the quality of the film. Thus, a film of the highest quality is formed on the substrate.

Preferably, the liquid suction and liquid delivery flow path and the pump chamber and liquid delivery flow path which communicate with each other of the suction pipe and the pump chamber are open in the peripheral region of the pump chamber, respectively. This arrangement improves the flow of the coating liquid through the pump chamber and reduces the possibility of the coating liquid remaining in the pump chamber.

Preferably, the control device operates such that the suction valve driving device and the delivery valve driving device open and close the suction valve and the delivery valve, respectively, and the pump driving device separates one side wall of the pump chamber in which the liquid suction and liquid delivery flow paths are opened. By moving to the side wall, the diaphragm pump sucks the coating liquid from the storage tank; The suction valve driver and the discharge valve driver then close the suction valve and open the discharge valve, and the pump drive moves the diaphragm in the opposite direction from one side wall to the other side wall so that the diaphragm pump is applied from the pump chamber to the nozzle. Discharging the liquid to discharge the coating liquid from the nozzle; The suction valve is then closed, the delivery valve is open, the pump drive is stopped for a while and the diaphragm pump then sucks the coating liquid into the pump chamber. With this control mode, the diaphragm pump performs suction.

While there are several drawings presently suitable for purposes of illustration of the present invention, they do not limit the precise arrangement and means of the present invention.

Preferred embodiments of the present invention will be described in detail later with reference to the drawings.

1 is a view showing the main part of a rotary coating device having a device for discharging a coating liquid for forming a silica film according to the present invention. 2 is a perspective view of a diaphragm pump used in the apparatus, and FIG. 3 is a longitudinal cross-sectional view of the diaphragm pump.

In this embodiment, the coating liquid applied to the surface of the substrate to form the silica film is a solution of a silicon composite such as a halogenated silane or an alkoxysilane dissolved in an organic solvent such as alcohol or ether, and a solution of a silica particle is sprayed in an organic solvent. Disperse mixed solutions. In another description of the present embodiment, the coating liquid for forming the silica film is simply referred to as silica coating liquid.

In Fig. 1, reference numeral 1 denotes a liquid storage tank for storing the silica coating liquid S. One end of the suction tube 2 extends to the silica coating liquid S stored in the liquid reservoir 1. The liquid reservoir 1 has a tube 1a for communicating the surrounding interior.

The other end of the suction pipe 2 is bound to the liquid suction port 3a of the diaphragm pump 3. One end of the liquid delivery pipe 4 is bound to the liquid delivery port 3b of the diaphragm pump 3. The diaphragm pump 3 has a pump driving tube 19 and valve driving tubes 24 and 25, and these tubes will be described later.

The other end of the liquid delivery pipe 4 communicates with the nozzle 5. The nozzle 5 has a discharge end 5a located substantially at the center of the rotation shaft 6 for supporting the wafer W under processing while rotating horizontally. The wafer W is placed so that the center of the wafer W coincides with the axis of rotation of the spin chuck 6.

In this state, the silica coating liquid S is discharged by a predetermined amount from the nozzle 5 and the discharge end 5a as described later. The discharged silica coating liquid S falls in the area around the center of the surface of the wafer W. As shown in FIG.

A centrifugal force is generated together with the rotating shaft 6 which rotates the wafer W, and the silica coating liquid S which has fallen flat on the surface of the wafer is diffused to apply silica having a uniform thickness on the surface of the wafer W. A film of liquid S is formed.

The rotating shaft 6 and the wafer W are surrounded by the scattering prevention cup 101 for preventing the silica coating liquid S from dispersing outward during the rotation of the wafer W. As shown in FIG.

The rotary coating device forms a film on a wafer, for example, by one of the following two sequences. In one sequence, the silica coating liquid S is dropped on the surface of the wafer W and then the wafer W is rotated to form a film thereon. In another squirrel, a film is formed by letting the silica coating liquid S fall on the surface of the rotating wafer W. In any case, it is necessary to supply the silica coating liquid S in a fixed amount to the surface of the wafer W for forming a film of uniform thickness. In this embodiment, as described later, the silica coating liquid S is always supplied to the surface of the wafer W in a fixed amount.

Next, the structure of the diaphragm pump 3 used in a present Example is demonstrated with reference to FIG. 2 and FIG.

As shown in FIG. 3, the liquid suction port 3a (liquid suction tube 2) and the pump chamber 11 of the diaphragm pump 3 have the first suction path 12 for the liquid suction, the suction valve 13, and the second suction path for the liquid suction. In communication with (14). The pump chamber 11 and the liquid delivery port 3b (liquid delivery tube 4) communicate with each other via the first delivery channel 15 for the liquid delivery, the delivery valve 16, and the second delivery channel 17 for the liquid delivery.

The pump chamber 11 has a diaphragm 18 extending therethrough. One end of the pump drive tube 19 (that is, the end extending into the diaphragm pump 3) communicates with the pump chamber 11, and the other end (extend out from the diaphragm pump 3) is a pump driver such as a piston. It is connected to (102). By depressurizing and pressurizing the pump chamber 11 by the pump driver 102, the diaphragm 18 reciprocates between sidewalls (between A and B in FIG. 3) in the pump chamber 11, thereby producing silica. It is comprised so that suction and sending of coating liquid S may be performed.

The pump driver 102 corresponds to a pump drive control means, and the drive control is configured to be performed by the controller 103 as a control means. The controller 103 is configured of, for example, a microcomputer.

Next, the configuration of the suction valve 13 and the delivery valve 16 will be described with reference to FIGS. 4A and 4B.

In addition, since the structure of the suction valve 13 and the delivery valve 16 are the same shape, the structure of the suction valve 13 is shown in FIG. 4A, 4B, and the suction valve 13 is demonstrated below as an example. 4A shows the closed state of the suction valve 13, and FIG. 4B shows the open state of the suction valve 13. As shown in FIG.

The suction valve 13 is closed when the deformable valve diaphragm 22 extending into the valve chamber 21 is clogged with the first flow passage 12 for liquid suction and the second flow passage 14 for liquid suction. 4a), and when the first flow passage 12 for liquid suction and the second flow passage 14 for liquid suction are in an open state (see also FIG. 4b). These open and closed states are changed by the three-way valve 23.

That is, in the case of the valve drive tube 24 and the delivery valve 16, the introduction end of the valve drive tube 25 is connected to the valve chamber 21, and the discharge end is the common port (CP) of the three passage valve 23. Is connected to). In addition, air is always supplied (pressurized) to the switching port P2 of the three-pass valve 23, and air is always sucked (decompressed) to the other switching port P2 side of the three-pass valve 23. When the switching ports P1 and P2 are switched to communicate the common port CP with the switching port P1, for example, as shown in FIG. 4A, the valve chamber 21 is pressurized by the supplied air. The valve membrane 22 is in a closed state in which the first flow passage 12 for liquid suction and the second flow passage 14 for liquid suction are blocked. On the other hand, when the common port CP and the switching port P2 communicate with each other, as shown in FIG. 4B, air in the valve chamber 21 is sucked in by suction, and the valve membrane 22 is connected to the valve driving pipe ( 24 is sucked to the introduction end side, and the first flow passage 12 for liquid suction and the second flow passage 14 for liquid suction are brought into an open state.

In addition, the three-pass valve 23 for changing the opening and closing of the suction valve 13 is a suction valve opening and closing means in the present invention, the discharge valve (three-way valve for changing the opening and closing (same configuration as the three-pass valve 23) is sent out in the present invention The switching control of each of these three-pass valves is driven so as to be performed by the controller 103 which performs drive control of the pump driver 102.

Next, the suction operation and the discharge operation of the silica coating liquid S by the diaphragm pump 3 will be described.

The suction operation of the diaphragm pump 3 opens the suction valve 13 in the open state, the discharge valve 16 in the closed state, depressurizes the pump chamber 11, and opens the diaphragm 18 (B side of FIG. In other words, the second flow path 14 for liquid suction and the first flow path 15 for liquid delivery are sucked to the A side as indicated by the dashed line). As a result, the silica coating liquid S is transferred from the liquid storage tank 1 to the liquid suction pipe 2, the first passage 12 for liquid suction (open state), the second passage for liquid suction ( It is sucked into the pump chamber 11 via 14). In addition, since the delivery valve 16 is in the closed state at this time, the backflow of the silica coating liquid S on the liquid delivery pipe 4 side is prevented.

On the other hand, in the delivery operation of the diaphragm pump 3, the suction valve 13 is closed, the delivery valve 16 is opened, the pump chamber 11 is pressurized, and the diaphragm 18 is solid (from the A side). As indicated by B, it is pushed in the opposite direction to the suction operation. As a result, the silica coating liquid S sucked into the pump chamber 11 is supplied with the first flow passage 15 for the liquid delivery, the delivery valve 16 (open state), the second flow passage 17 for the liquid delivery, It is sent to the nozzle 5 via the liquid delivery pipe 4. The silica coating liquid S supplied to the nozzle 5 discharges to the surface of the wafer W. As shown in FIG. In addition, at this time, since the suction valve 13 is in the closed state, the silica coating liquid S to be sent is prevented from flowing back to the liquid suction pipe 2 side.

By such a suction and delivery operation (single stroke) by the diaphragm pump 3, the amount of silica coating liquid S required for film formation is discharged from the nozzle 5 to the surface of the wafer W, The diaphragm pump 3 is comprised.

As described above, the liquid reservoir 1 is provided with a tube 1a communicating with the inside of the liquid reservoir 1 and the atmosphere, so that the silica coating liquid (2) is passed through the liquid suction pipe 2 by the diaphragm pump 3. When S) is attracted, the inside of the liquid reservoir 1 is prevented from depressurizing. Therefore, the suction amount of the silica coating liquid S is always constant by one suction operation by the diaphragm pump 3.

The following effects are obtained by discharging the silica coating liquid S stored in the liquid storage tank 1 to the surface of the wafer W using the above-described Example apparatus.

First, since gas is not used to discharge the silica coating liquid S stored in the liquid storage tank 1 to the surface of the substrate W, gas does not dissolve in the silica coating liquid S, There is no degassing after application of the coating liquid to the surface of the wafer W. Therefore, obstacles such as pinholes and coating stains caused by these are eliminated.

In addition, when the coating liquid is pumped from the liquid reservoir to the nozzle by the gas pressure and discharged to the surface of the wafer W, a predetermined amount of the predetermined amount is applied to the surface of the wafer W by the arrangement of the supply pipes from the liquid reservoir to the nozzle. There is also a problem that the control degree for discharging the coating liquid becomes poor. For example, if there is a place where the supply pipe from the liquid reservoir to the nozzle is bent rapidly, the flow of the coating liquid there will be bad, and even if the coating liquid is pushed under the same gas pressure, a predetermined amount of the coating liquid will It is not discharged to the surface.

On the other hand, when the diaphragm pump 3 is used, the degree of control of the discharge amount of a coating liquid can be improved. That is, irrespective of the arrangement of the tubes, the diaphragm pump 3 is always drawn with a constant amount of coating liquid, and the diaphragm pump 3 is always fed with a constant amount of coating liquid. Therefore, a constant amount of coating liquid is always discharged to the surface of the wafer W. As shown in FIG.

In addition, when the suction and delivery of the silica coating liquid S are carried out by a bellows pump, the silica coating liquid S remains in the bellows pump for a long time. That is, when sending out the silica coating liquid S sucked from the bellows pump, the bellows are shrunk or a space is formed in the bellows even at the time of maximum shrinkage, so that the space of the silica coating liquid S sucked into the space is reduced. Some remain. In addition, a part of the silica coating liquid S remaining in subsequent suction and discharging operations remains, and as a result, the silica coating liquid S remains in the bellows pump for a long time.

On the other hand, when the diaphragm pump 3 is used, when the silica coating liquid S is sent out, the diaphragm 18 adheres to the liquid delivery flow path (the first flow path 15 for liquid delivery in the above embodiment) (or Approaching), there is no space in the pump chamber chamber 11 (or stays while a small space is formed) at the time of delivery, and almost all of the sucked silica coating liquid S is sent out from the pump chamber 11. As a result, crystals of the silica coating liquid S are less likely to be formed in the pump chamber 11, and discharge of the silica coating liquid S in which the crystals are mixed to the surface of the wafer W is reduced. Therefore, there is no deterioration of the film quality caused by discharging the silica coating liquid S in which the crystals are mixed to the surface of the wafer W, so that a good film can be obtained.

In addition, when the experiment of forming a film on the wafer W is carried out using the above-described embodiment, the following good results are obtained.

Experimental condition

(1) The diaphragm pressure of the diaphragm pump 3 shall be 0.1 kg / cm <2>.

(2) The silica coating liquid S was discharged at 1-2 cc / sheet on the surface of the wafer W having a diameter of 6 inches.

Experiment result

There is no coating stain due to bubbles and crystals, and the film thickness of the formed film becomes almost uniform. In addition, when the silica coating liquid S is discharged by the gas pressure of nitrogen gas, the bubble of the nitrogen gas dissolved in the silica coating liquid S in the supply pipe was visually observed using silica in this example. In the case of discharging the coating liquid S, bubbles of gas dissolved in the silica coating liquid S were not observed in the supply pipes (liquid suction tube 2 and liquid discharge tube 4).

However, the pump chamber of the conventional general diaphragm pump has a large curvature of the inner wall of the pump chamber 11 (as shown in FIG. And the second flow passage 14 for liquid suction and the first flow passage 15 for liquid delivery are gathered in the center line CL of the pump chamber 11 and are connected to each other. However, in such a configuration, the flow of liquid is reduced at the portion of the edge E in the pump chamber 11. As a result, a small amount of liquid remains in the pump chamber 11. Therefore, the edge E of the pump chamber 11 is shaped along the chain line in FIG. 5A (the width of the center portion is narrow with respect to the extension direction of the diaphragm) to make the shape near the edge E slippery, and the liquid The second flow passage 14 for suction and the first flow passage 15 for liquid delivery are connected in close proximity to the edge E of the pump chamber 11 to form the fifth pump so that the diaphragm pump 3 is connected. It is preferable to construct. When the diaphragm pump configured in this way is applied to this embodiment, the flowability of the silica coating liquid S in the pump chamber 11 is further improved, and the pump chamber 11 is compared with the conventional diaphragm pump (of FIG. 5A). The residual of the silica coating liquid S in the inside can be further reduced.

In addition, the center portion (near CL) of the pump chamber 11 of FIG. 5B is a portion where the displacement of the diaphragm 18 is inherently good and the flowability of the liquid is good, so that the second flow passage 14 for liquid suction and the first flow passage for liquid delivery are shown. Even if 15 is shifted to the edge E side of the pump chamber 11, a liquid does not remain in this part.

In addition, conventionally, this type of coating liquid discharge device is generally provided with a stone back mechanism to prevent liquid leakage after discharging of the coating liquid. That is, when the coating liquid is undesirably dropped from the nozzle 5 while the predetermined amount of the coating liquid is discharged onto the surface of the wafer W to rotate the wafer W to diffuse the coating liquid (liquid leakage occurs It is known that a film of uniform film thickness is not formed. Thus, after discharging a predetermined amount of the coating liquid onto the wafer W, a mechanism (seat-back mechanism) for reabsorbing the coating liquid from the nozzle is provided. However, it is not preferable to separately provide a special stone bag mechanism for preventing this liquid leakage, because the apparatus configuration is complicated and the cost is high.

Thus, in the present embodiment, the diaphragm is controlled by the suction, the discharging operation by the diaphragm 18 of the diaphragm pump 3 and the control of the opening and closing operation timing of the suction valve 13 and the discharging valve 16 as follows. It is possible to give the pump 3 a seat back function.

This control will be described with reference to FIG.

FIG. 6 is a timing chart for explaining the control for performing the back and back in the diaphragm pump 3.

One point in the figure is the point of time when the discharging operation by the diaphragm 18 is completed, that is, until the diaphragm 18 is in the solid line state (B side) of FIG. At this time, the delivery valve 16 is in an open state, and the suction valve 13 is in a closed state. Then, the pump driver 102 is stopped for a short time before the next suction operation is started, and the pump driver 102 is not infiltrated into the pump chamber 11 (stop of the pump driver 102 in FIG. 6). In addition, the delivery valve 16 is not immediately closed at one time point, but is closed at two time points after t _one hour has elapsed at _one time point. By controlling in this way, a predetermined amount of coating liquid is discharged from the nozzle 5 until the completion of delivery (at one point in time). Thereafter, the diaphragm 18 is not subjected to the force in the pump driver 102, so that the diaphragm 18 is slightly returned to the A side by the reaction which is pushed to the side wall on the B side in FIG. At this time, since the delivery valve 16 is in an open state, a small amount of the coating liquid is returned from the nozzle 5 via the liquid delivery pipe 4 or the like.

By setting this time as t ₁ "0.1 seconds", it is possible to achieve a good function seokbaek main surface by operating the device in a diaphragm pump (3).

In addition, as shown in FIG. 7A, in the above-described embodiment, a filter (filter) is provided in the flow path of the silica coating liquid S of the liquid suction pipe 2 between the liquid reservoir 1 and the diaphragm pump 3. (104) may be attached.

By configuring in this way, the foreign matter (dust) etc. which were mixed in the silica coating liquid S stored in the liquid storage tank 1 were filtered with the filter 104, and the diaphragm pump 3 and the liquid discharge pipe ( 4) It can discharge to the surface of the wafer W through the nozzle 5, and can improve film quality.

As shown in Fig. 7B, a needle valve 105 for adjusting the flow rate may be provided between the diaphragm pump 3 and the nozzle 5 so that the discharge amount of the coating liquid can be finely adjusted.

In addition, as shown in FIG. 7C, the filter 104 is attached to the flow path of the silica coating liquid S of the liquid suction pipe 2, and at the same time, the flow rate between the diaphragm pump 3 and the nozzle 5 is maintained. An adjustment needle valve 105 or the like may be provided.

The present invention can be carried out in other specific forms without departing from the spirit or essence thereof, and therefore, reference should be made to the appended claims as well as the above description as indicating the scope of the invention.

Claims (9)

An apparatus for discharging a coating liquid for forming a silica film for forming a silica film on a surface of a substrate by dropping a silica coating liquid on a substrate surface subjected to horizontal rotation coating, comprising: a liquid storage tank for storing the coating liquid; A nozzle facing the surface of the substrate for discharging the coating liquid, a diaphragm pump for sucking the coating liquid from the liquid reservoir and sending the coating liquid to the nozzle, and one end of which is stored in the liquid reservoir Coating for forming a silica film having a suction pipe extending from the coating liquid, the other end connected to the suction port of the diaphragm pump, and the discharge pipe having one end connected to the discharge port of the diaphragm pump and the other end connected to the nozzle. Apparatus for discharging the liquid. The diaphragm pump according to claim 1, wherein the diaphragm pump includes a pump chamber having a diaphragm extending through the diaphragm pump, a suction valve for opening and closing a liquid suction flow path for communicating the suction pipe with the pump chamber, and the discharge pipe. And a delivery valve for opening and closing a fluid delivery flow path for communicating the pump chamber with each other, the apparatus comprising: pump driving means for reciprocating the diaphragm in the pump chamber, and for operating the suction valve. A delivery valve driving means, and a control means for controlling the pump driving means, the suction valve driving means, and the delivery valve driving means, wherein the diaphragm pump is formed to form a silica film which is driven to draw and feed the coating liquid. Apparatus for discharging the coating liquid for. 3. The suction valve according to claim 2, wherein the suction valve includes a first valve chamber arranged in the liquid suction flow passage, and a first valve diaphragm which is provided in the valve chamber and is deformable. The first valve diaphragm deforms in a state in which the liquid suction first flow path extending to the chamber and the liquid suction second flow path extending from the first valve chamber to the pump chamber are in close communication with each other; It is configured to operate to open and close the liquid suction flow path, wherein the delivery valve is provided with a second valve chamber arranged in the liquid delivery flow path, and a second valve diaphragm that is provided in the second valve chamber and is deformable, And in communication with a state of closing a first flow passage extending from the pump chamber to the second valve chamber and a second flow passage extending from the second valve chamber to the discharge pipe. An apparatus for discharging a second coating for the valve diaphragm is deformed to form the solution of silica is configured to operate in opening and closing the delivery passage in the liquid film state. 3. The apparatus for discharging a coating liquid for forming a silica film according to claim 2, wherein the liquid suction passage and the liquid discharge passage are opened to a peripheral region of the pump chamber. 3. The control means according to claim 2, wherein the control means is operated to close the delivery valve so that the suction valve driving means and the delivery valve driving means open the suction valve, and the pump driving means is used for the liquid suction. The diaphragm pump moves the diaphragm from the one side wall of the pump chamber in which the flow path and the liquid delivery flow path are opened to the other side, so that the diaphragm pump sucks the coating liquid from the liquid reservoir, and then the suction valve driving means and the A delivery valve driving means is operated to close the suction valve and the delivery valve, respectively, and the pump driving means moves the diaphragm in the opposite direction from the other side wall to the one side wall, so that the diaphragm pump is connected to the pump chamber. Discharging the coating liquid from the nozzle by discharging the coating liquid from the nozzle to the nozzle, and then And the dispensing valve from the held state to the open state by stopping for a short time the pump driving means the diaphragm pump in an apparatus for silica film discharging a coating solution for forming are configured to be operated to suction the coating solution into the pump chamber. The apparatus for discharging the coating liquid for forming a silica film according to claim 1, further comprising a filter mounted in an intermediate portion of the suction pipe. The apparatus for discharging the coating liquid for forming a silica film according to claim 1, further comprising a discharge valve for adjusting a discharge flow rate mounted on an intermediate portion of said delivery pipe. An apparatus for discharging a coating liquid for forming a silica film to form a silica film on the substrate surface by dropping a silica coating liquid on a substrate surface under a horizontal rotation coating treatment, includes a liquid storage tank for storing the coating liquid; A nozzle facing the substrate surface for discharging the coating liquid, and a diaphragm pump for sucking the coating liquid from the liquid storage tank and feeding the coating liquid to the nozzle, wherein the diaphragm pump extends through the diaphragm pump. A pump chamber having a pump, a suction valve for opening and closing a liquid suction flow path for communicating the suction pipe with the pump chamber, a discharge valve for opening and closing a liquid discharge flow path for communicating the discharge pipe and the pump chamber with each other; And one end extending into the coating liquid stored in the liquid reservoir and the other end connected to the liquid suction port of the diaphragm pump. A suction pipe having a suction pipe, a discharge pipe having one end connected to the liquid discharge port of the diaphragm pump and the other end connected to the nozzle, pump driving means for reciprocating the diaphragm in the pump chamber, and operating the suction valve. A silica membrane comprising a suction valve driving means for driving, a driving means for driving a delivery valve for operating the delivery valve, and a control means for controlling the pump driving means, the suction valve driving means and the delivery valve driving means. An apparatus for discharging a coating liquid for forming. The suction valve driving means and the discharge valve driving means open the suction valve and the discharge valve, respectively, and the pump driving means comprises the suction flow path and the discharge flow path. Move the diaphragm from one side wall of the pump chamber to the other side wall so that the diaphragm pump sucks the coating liquid from the liquid reservoir, and then the suction valve driving means and the delivery valve driving means The pump driving means moves the diaphragm in the opposite direction from the other side wall to the one side wall by opening and closing the valve and the delivery valve, so that the diaphragm pump delivers the coating liquid from the pump chamber to the nozzle and After discharging the coating liquid from the nozzle, the suction valve is closed and the delivery valve is kept open. And stopping the pump driving means for a while to discharge the coating liquid for forming a silica film so that the diaphragm pump sucks the coating liquid into the pump chamber.